/**
 * @class Ext.tree.TreeCheckNodeUI
 * @extends Ext.tree.TreeNodeUI
 *
 * Some extends features available:
 * (1) single check model (allow only one treeNode checked)
 *		usage:  checkModel: "single"
 * (2) cascade check model (when check/uncheck a node,will auto check/uncheck it's childrenNodes, and it's all parentNodes,suport asyn's node loads situation)
 *		usage:  checkModel: "cascade"
 * (3) only leaf node can check model
 *		only when the node's attribute leaf is true,then the node has checkbox
 *		usage:  onlyLeafCheckable: true  , default is false,all nodes have checkbox
 *
 * checkModel default is 'multiple' , then all node with checkbox can checked
 *
 * Supported events:
 * check (when the node's checkbox value change, will fire this event)
 *
 * usage:
 *    just add attribute  baseAttrs: { uiProvider: Ext.ux.TreeCheckNodeUI }  to tree's loader
 *
 * for example:
 *
 *   var tree = new Ext.tree.TreePanel({
 *		el:'tree-ct',
 *		width:568,
 *		height:300,
 *		checkModel: 'cascade',   // cascade check
 *		onlyLeafCheckable: false,// all node have checkbox
 *		animate: false,
 *		rootVisible: false,
 *		autoScroll:true,
 *		loader: new Tree.TreeLoader({
 *			dataUrl:'get-nodes.php'
 *			baseAttrs: { uiProvider: Ext.tree.TreeCheckNodeUI } //add uiProvider attribute
 *		}),
 *		root: new Ext.tree.AsyncTreeNode({ id:'0' })
 *	});
 *	tree.on("check",function(node,checked){alert(node.text+" = "+checked)});
 *	tree.render();
 */

Ext.tree.TreeCheckNodeUI = function() {
    //'multiple': multiple check model; 'single': single check model; 'cascade':cascade check model
    this.checkModel = 'multiple';

	//only leaf node has checkbox
    this.onlyLeafCheckable = false;

    Ext.tree.TreeCheckNodeUI.superclass.constructor.apply(this, arguments);
};

Ext.extend(Ext.tree.TreeCheckNodeUI, Ext.tree.TreeNodeUI, {

    renderElements : function(n, a, targetNode, bulkRender) {
        var tree = n.getOwnerTree();
        this.checkModel = tree.checkModel || this.checkModel;
        this.onlyLeafCheckable = tree.onlyLeafCheckable || false;

        // add some indent caching, this helps performance when rendering a large tree
        this.indentMarkup = n.parentNode ? n.parentNode.ui.getChildIndent() : '';

        //var cb = typeof a.checked == 'boolean';
        var cb = (!this.onlyLeafCheckable || a.leaf);
        var href = a.href ? a.href : Ext.isGecko ? "" : "#";
        var buf = ['<li class="x-tree-node"><div ext:tree-node-id="',n.id,'" class="x-tree-node-el x-tree-node-leaf x-unselectable ', a.cls,'" unselectable="on">',
            '<span class="x-tree-node-indent">',this.indentMarkup,"</span>",
            '<img src="', this.emptyIcon, '" class="x-tree-ec-icon x-tree-elbow" />',
            '<img src="', a.icon || this.emptyIcon, '" class="x-tree-node-icon',(a.icon ? " x-tree-node-inline-icon" : ""),(a.iconCls ? " " + a.iconCls : ""),'" unselectable="on" />',
            cb ? ('<input class="x-tree-node-cb" type="checkbox" ' + (a.checked ? 'checked="checked" />' : '/>')) : '',
            '<a hidefocus="on" class="x-tree-node-anchor" href="',href,'" tabIndex="1" ',
            a.hrefTarget ? ' target="' + a.hrefTarget + '"' : "", '><span unselectable="on">',n.text,"</span></a></div>",
            '<ul class="x-tree-node-ct" style="display:none;"></ul>',
            "</li>"].join('');

        var nel;
        if (bulkRender !== true && n.nextSibling && (nel = n.nextSibling.ui.getEl())) {
            this.wrap = Ext.DomHelper.insertHtml("beforeBegin", nel, buf);
        } else {
            this.wrap = Ext.DomHelper.insertHtml("beforeEnd", targetNode, buf);
        }

        this.elNode = this.wrap.childNodes[0];
        this.ctNode = this.wrap.childNodes[1];
        var cs = this.elNode.childNodes;
        this.indentNode = cs[0];
        this.ecNode = cs[1];
        this.iconNode = cs[2];
        var index = 3;
        if (cb) {
            this.checkbox = cs[3];
            Ext.fly(this.checkbox).on('click', this.check.createDelegate(this, [null]));
            index++;
        }
        this.anchor = cs[index];
        this.textNode = cs[index].firstChild;
    },

    // private
    check : function(checked) {
        var n = this.node;
        var tree = n.getOwnerTree();
        this.checkModel = tree.checkModel || this.checkModel;

        if (checked === null) {
            checked = this.checkbox.checked;
        } else {
            this.checkbox.checked = checked;
        }

        n.attributes.checked = checked;
        tree.fireEvent('check', n, checked);

        if (!this.onlyLeafCheckable && this.checkModel == 'cascade') {
            var parentNode = n.parentNode;
            if (parentNode !== null) {
                this.parentCheck(parentNode, checked);
            }
            if (!n.expanded && !n.childrenRendered) {
                n.expand(false, false, this.childCheck);
            }
            else {
                this.childCheck(n);
            }
        } else if (this.checkModel == 'single') {
            var checkedNodes = tree.getChecked();
            for (var i = 0; i < checkedNodes.length; i++) {
                var node = checkedNodes[i];
                if (node.id != n.id) {
                    node.getUI().checkbox.checked = false;
                    node.attributes.checked = false;
                    tree.fireEvent('check', node, false);
                }
            }
        }

    },

    // private
    childCheck : function(node) {
        var a = node.attributes;
        if (!a.leaf) {
            var cs = node.childNodes;
            var csui;
            for (var i = 0; i < cs.length; i++) {
                csui = cs[i].getUI();
                if (csui.checkbox.checked ^ a.checked)
                    csui.check(a.checked);
            }
        }
    },

    // private
    parentCheck : function(node, checked) {
        var checkbox = node.getUI().checkbox;
        if (typeof checkbox == 'undefined')return;
        if (!(checked ^ checkbox.checked))return;
        if (!checked && this.childHasChecked(node))return;
        checkbox.checked = checked;
        node.attributes.checked = checked;
        node.getOwnerTree().fireEvent('check', node, checked);

        var parentNode = node.parentNode;
        if (parentNode !== null) {
            this.parentCheck(parentNode, checked);
        }
    },

    // private
    childHasChecked : function(node) {
        var childNodes = node.childNodes;
        if (childNodes || childNodes.length > 0) {
            for (var i = 0; i < childNodes.length; i++) {
                if (childNodes[i].getUI().checkbox.checked)
                    return true;
            }
        }
        return false;
    },

    //private
    toggleCheck : function(value) {
        var cb = this.checkbox;
        if (cb) {
            var checked = (value === undefined ? !cb.checked : value);
            this.check(checked);
        }
    }
});